Bug 52505

Summary: [avr]: __memx address space reading unintentionally from RAM
Product: gcc Reporter: Georg-Johann Lay <gjl>
Component: targetAssignee: Georg-Johann Lay <gjl>
Status: RESOLVED FIXED    
Severity: normal Keywords: wrong-code
Priority: P5    
Version: 4.7.0   
Target Milestone: 4.7.1   
Host: Target: avr
Build: Known to work:
Known to fail: Last reconfirmed: 2012-03-06 00:00:00

Description Georg-Johann Lay 2012-03-06 11:25:53 UTC
The __memx address space reader must determine at runtime from what memory area to read and what instruction to use. To read one byte, ine sequence might look like:

	ld   r24,Z
	sbrs r25,7
	lpm  r24,Z

This is not correct because if the read is fram flash memory but the address taken as RAM address points to the I/O area, the read might have an effect on I/O register, for example clear a latch or buffer.
Comment 1 Georg-Johann Lay 2012-03-07 10:36:34 UTC
Author: gjl
Date: Wed Mar  7 10:36:30 2012
New Revision: 185031

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=185031
Log:
libgcc/
	PR target/52505
	* config/avr/lib1funcs.S (__xload_1): Don't read unintentionally
	from RAM.

gcc/
	PR target/52505
	* config/avr/avr.c (avr_out_xload): Don't read unintentionally
	from RAM.
	* config/avr/avr.md (xload_8): Adjust insn length.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/avr/avr.c
    trunk/gcc/config/avr/avr.md
    trunk/libgcc/ChangeLog
    trunk/libgcc/config/avr/lib1funcs.S
Comment 2 Georg-Johann Lay 2012-03-22 15:07:13 UTC
Author: gjl
Date: Thu Mar 22 15:06:57 2012
New Revision: 185697

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=185697
Log:
libgcc/
	Backport from 2012-03-07 mainline r185033.

	PR target/52507
	* config/avr/lib1funcs.S (__movmemx_hi): Fix loop label in RAM-part.

	Backport from 2012-03-07 mainline r185031.

	PR target/52505
	* config/avr/lib1funcs.S (__xload_1): Don't read unintentionally
	from RAM.

	Backport from 2012-03-07 mainline r185030.

	PR target/52461
	PR target/52508
	* config/avr/lib1funcs.S (__do_copy_data): Clear RAMPZ after usage
	if RAMPZ affects reading from RAM.
	(__tablejump_elpm__): Ditto.
	(.xload): Ditto.
	(__movmemx_hi): Ditto.
	(__do_global_ctors): Right condition for RAMPZ usage is "have ELPM".
	(__do_global_dtors): Ditto.
	(__xload_1, __xload_2, __xload_3, __xload_4): Ditto.
	(__movmemx_hi): Ditto.

gcc/
	Backport from 2012-03-22 mainline r185692.

	PR target/52496
	* config/avr/avr.md (unspec): Remove UNSPEC_MEMORY_BARRIER.
	(unspecv): Add UNSPECV_MEMORY_BARRIER.
	(cli_sei): Use unspec_volatile instead of unspec for memory barrier.
	(delay_cycles_1, delay_cycles_2): Ditto.
	(delay_cycles_3, delay_cycles_4): Ditto.
	(nopv, *nopv): Ditto.
	(sleep, *sleep): Ditto.
	(wdr, *wdr): Ditto.

	Backport from 2012-03-21 mainline r185605.

	PR rtl-optimization/52543
	PR target/52461
	* config/avr/avr-protos.h (avr_load_lpm): New prototype.
	* config/avr/avr.c (avr_mode_dependent_address_p): New function.
	(TARGET_MODE_DEPENDENT_ADDRESS_P): New define.
	(avr_load_libgcc_p): Restrict to __flash loads.
	(avr_out_lpm): Only handle 1-byte loads from __flash.
	(avr_load_lpm): New function.
	(avr_find_unused_d_reg): Remove.
	(avr_out_lpm_no_lpmx): Remove.
	(adjust_insn_length): Handle ADJUST_LEN_LOAD_LPM.
	* config/avr/avr.md (unspec): Add UNSPEC_LPM.
	(load_<mode>_libgcc): Use UNSPEC_LPM instead of MEM.
	(load_<mode>, load_<mode>_clobber): New insns.
	(mov<mode>): For multi-byte move from non-generic
	16-bit address spaces: Expand to load_<mode> resp.
	load_<mode>_clobber.
	(load<mode>_libgcc): Remove expander.
	(split-lpmx): Remove split.

	Backport from 2012-03-13 mainline r185329.

	PR target/52488
	* config/avr/avr.c (avr_prologue_setup_frame): Cut down stack
	offset (size) to a value the insns can deal with.
	(expand_epilogue): Ditto.

	Backport from 2012-03-12 mainline r185256.

	PR target/52499
	* config/avr/avr.c (avr_mode_code_base_reg_class): Change return
	type from reg_class_t to enum reg_class.
	* config/avr/avr-protos.h (avr_mode_code_base_reg_class): Ditto.

	Backport from 2012-03-12 mainline r185253.

	PR target/52148
	* config/avr/avr.c (avr_out_movmem): Fix typo in output template
	for the case ADDR_SPACE_FLASH and AVR_HAVE_LPMX introduced in
	r184615 from 2012-02-28.

	Backport from 2012-03-08 mainline r185105.

	* config/avr/avr.md (*addhi3, addhi3_clobber): Add "w" alternative
	for constants in [-63,63].

	Backport from 2012-03-08 mainline r185100.

	PR target/52496
	* config/avr/avr.c (avr_mem_clobber): New static function.
	(avr_expand_delay_cycles): Add memory clobber operand to
	delay_cycles_1, delay_cycles_2, delay_cycles_3, delay_cycles_4.
	* config/avr/avr.md (unspec): Add UNSPEC_MEMORY_BARRIER.
	(enable_interrupt, disable_interrupt): New expander.
	(nopv, sleep, wdr): New expanders.
	(delay_cycles_1): Add memory clobber.
	(delay_cycles_2): Add memory clobber.
	(delay_cycles_3): Add memory clobber.
	(delay_cycles_4): Add memory clobber.
	(cli_sei): New insn from former "enable_interrupt",
	"disable_interrupt" with memory clobber.
	(*wdt): New insn from former "wdt" with memory clobber.
	(*nopv): Similar, but for "nopv".
	(*sleep): Similar, but for "sleep".

	Backport from 2012-03-07 mainline r185043.

	PR target/52484
	* config/avr/avr.md (xload<mode>_A): Add R22... to register footprint.

	Backport from 2012-03-07 mainline r185032.

	PR target/52506
	* gcc/config/avr/avr.c (expand_epilogue): Fix order of restoration
	to: RAMPZ, RAMPY, RAMPX, RAMPD.
	(expand_prologue): Only clear RAMPZ if it has effect on RAM-read.

	Backport from 2012-03-07 mainline r185031.

	PR target/52505
	* config/avr/avr.c (avr_out_xload): Don't read unintentionally
	from RAM.
	* config/avr/avr.md (xload_8): Adjust insn length.

	Backport from 2012-03-07 mainline r185030.

	PR target/52461
	* gcc/config/avr/avr.c (avr_out_lpm): Clear RAMPZ after usage
	if RAMPZ affects reading from RAM.

	Backport from 2012-03-05 mainline r184919.

	* config/avr/avr.md (*umaddqihi4.2): New insn-and-split.


Modified:
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/config/avr/avr-protos.h
    branches/gcc-4_7-branch/gcc/config/avr/avr.c
    branches/gcc-4_7-branch/gcc/config/avr/avr.md
    branches/gcc-4_7-branch/libgcc/ChangeLog
    branches/gcc-4_7-branch/libgcc/config/avr/lib1funcs.S
Comment 3 Georg-Johann Lay 2012-03-22 15:29:43 UTC
Fixed in 4.7.1